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The Global Magazine of Leica Geosystems
Dear Readers, Leica Geosystems is a renowned leader in the development and manufacturing of surveying measurement instruments. With a history dating back to Wild and Kern we have plenty of track records and “world’s first” products to back up this statement. Since Hexagon acquired Leica Geosystems, extensive planning has been done in order to also position us as a leading supplier of measurement instruments and tools for construction applications. One key area we are focusing on is Machine Control (MC), using GPS technologies to monitor and direct construction vehicles. In this issue of the Reporter you will see some exciting new projects realized with Leica Geosystems Machine Control technology around the world. Since last summer we have acquired three companies in this area: Scanlaser, a leading systems integrator of MC, Mikrofyn, a leading sensor and laser manufacturer within the MC segment, and SBG, a leading software manufacturer for MC solutions. With these companies and combined with the inherent knowledge within Leica Geosystems for sensors (TPS and GPS) and software, we now have a strong technical as well as commercial base in MC in Europe. We will continue our growth in this expanding market during 2007. In the past year we have put a lot of effort into enhancing our product offering in the measurement tools area. At BAUMA we will show you the integrated solutions we recognize as the key to success on every construction site. Beyond our range of MC products across all applications – from Grading and Excavating to Paving – construction and indoor tools like the new Leica Rugby 50 and Leica Rugby 55, and of course the brand new Leica LINO™ L2, underline our power in the world of the construction site.
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CONTENTS
Editorial
in this issue: 03 Leica Geosystems Protects Venice 06 Swedish Underground 08 In the Middle of the Rhine 09 Non-stop Paving 10 Leica Builder in the “Green Industry” 12 Rising High with GPS Network 14 Russia goes for Leica ADS40 16 Earth Dam Monitoring with GPS Survey 18 Keeping Track of Moving Structures 20 Beyond Scanning 21 Keep Up With the Youngsters 22 Sharp Lines on Site 23 News/Imprint
Get a taste of the new Leica Geosystems construction venture for yourself – with the Reporter 56 and at BAUMA!
Ola Rollén CEO Hexagon and Leica Geosystems
Leica Geosystems Protects Venice by Emilio Palchetti
The 20th century has certainly endangered Venice’s ability to keep itself above water in the Venetian Lagoon. The city ever more frequently falls victim to intensive flooding, which not only reduces the quality of life for Venetians but also causes considerable damage to their architectural heritage. Following the evaluation of numerous alternatives the “Mose� project, an ingenious protection system, which includes adjustable floodgates, is now being imple-
mented. A machine automation solution with GPS from Leica Geosystems has been chosen to ensure their exact positioning. Over the last one hundred years Venice has subsided relative to mean sea level by about 23 cm, while the tidal range has increased by about 8 cm due to morphological changes in the lagoon bed. The Ministry for Infrastructure designed an integrated intervention system to protect the city against high water levels: these include local protection measures to save the lowest-lying parts of the city and flood defences at
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As soon as the water level exceeds the critical value of 110 cm, air is pumped into the floodgates, which rise from the sea bed to keep back the water.
the entrance to the lagoon, both of which will come into action as soon as the water level rises by more than 110 cm.
The Mose system As soon as this mark is reached, 78 adjustable floodgates at the entrances to the lagoon (18 in Chioggia, 19 in Malamocco and 41 at Lido) are activated to separate the city from the open sea. Further protection measures include various initiatives to lower water levels in the lowest-lying areas of the city during the very frequent flooding. All measures are augmented by an extremely effective protection system, which optimises the management of the gates and limits closure of the inlets to 3 to 5 occasions per year to preserve water quality and protect morphology, landscape and harbour activities.
Works at sea One of the first contracts, for the foundations to anchor the floodgate modules, was awarded to Grandi Lavori Fincosit S.p.a. The work was situated in the area of the harbour entrance at Lido di Venezia: 176 steel piles, each 24 m long and 508 mm in diameter, were to be anchored in the sea bed more
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than 16 m below water level in a 3 x 3 m grid. What is a routine operation on land had to be performed at sea without fixed reference points and in occasionally unfavourable environmental conditions such as marine currents, tides and strong Bora winds. At the same time, the requirements were very strict with the maximum permissible deviation from plan being 15 cm. Surveyor Giulio Salvador of Grandi Lavori Fincosit S.p.a. and engineer Filippo Rettondini of the subcontractor VIPP Lavori S.p.a., technical manager of foundation works, explained the challenging task they faced to the team from Leica Geosystems Machine Automation: First, a piling rig had to be transported into position at the driving site and similar measures taken as on land to secure it in place. Then it was up to the machine operator to drive the piles to the highest possible accuracy directly over the specified design coordinates.
Positioning the piling rig To complete this first part of the operation, they used the self-elevating platform “Lynx� provided by Grandi Lavori Fincosit. This is specially designed to
A1
Exact Control The experts at Leica Geosystems developed a navigation system consisting of two antenna (A1, A 2), a GPS receiver (B) and a special control program to allow the machine operator to position the piles as precisly as possible. The piles can be placed exactly at the position specified on the drawings and driven into the sea bed by the rig. An inclination sensor (D) provides the machine operator with all the necessary information to sink each pile exactly vertically.
A2
C
D
B A1 , A2
Antenna
B
GPS receiver
C
Computer with control program
D
Inclination sensor
transport large machines over water, in this case a piling rig, and when required transforms into a fixed platform anchored to the sea bed with the aid of four telescopic elements attached to its sides. The team from Leica Geosystems specially developed a GPS system to determine the coordinates of the Lynx, which would guide the pontoon operator to the best possible anchoring position. The objective was to obtain the ideal position for the rig so that it could place as many piles as possible from each set-up and reduce to a minimum the time needed to reposition the pontoon when finished at one site.
Positioning the piles For the second requirement, namely to help the rig operator place the piles exactly in the specified positions, the team developed a supporting navigation system based the Leica GSM5-M20 GPS receiver. The receiver, two antenna and appropriate control software display the planimetric position of the antenna on the rig in relation to the specified coordinates to the rig operator.
able to position the ram’s antenna very quickly over the coordinates for the pile, taking into account the minimum tolerances. The software can also provide stored reports on the driving of the piles if necessary with information on how far the installed position deviates from the specified position of the pile. This provides a simple way of creating a certification report attesting to the quality of the work performed in relation to the required standard. Thanks to this innovative GPS positioning solution the foundation works for the Mose project in Venice were completed in the shortest possible time. With this project Leica Geosystems was able to contribute to saving the city of Venice, which is unfortunately still at the mercy of natural forces of decay, in a very real way.
The operator simply compares the reference points on the monitor graphically and numerically and is
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Swedish Underground by Klas Hultman
One of the main requirements during the construction of the new Citytunnel in Malmö is to ensure that the surrounding buildings do not settle as a result of the tunnel driving works – as so often is the case with underground railway projects. Therefore daily monitoring surveys are carried out to allow immediate action to be taken should any buildings show signs of movement. With the new rail connection in place, train passengers will no longer have to go the long way round the city to reach Malmö’s main station but instead will be taken underground for a part of the journey. They will pass through two new stations: one is situated at the square known as “Triangeln” (The Triangle) in the centre of Malmö, whilst the other is in the development district of “Hyllie” in the south-west corner of the city. The surveying tasks associated with the construction of this new rail link are challenging and multifaceted. The maximum allowable deviation when tunnel-driving is 10 cm. At the same time the
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underground work must not cause any kind of damage to the buildings above. Mr. Kenn Hoby Andersen, surveying engineer with Aarsleff A/S and responsible for the construction of the Citytunnel in Malmö, makes it clear that there is always a risk that buildings will settle when a tunnel is installed under a built-up area: "This has happened before on many underground rail construction sites. One of the most serious cases was about 13 years ago in Munich. In one tunnel the ground failed and a bus fell into one of the cracks. That is of course an example of an absolute catastrophe, but it is normal for the buildings in the surrounding area to suffer cracks as a result of settlement. These cracks should be taken very seriously. Therefore we carry out daily monitoring surveys so that we are always one step ahead and can introduce immediate measures if anything changes," he explains.
One step ahead with monitoring surveys The surveying engineers carry out daily monitoring with an invar staff using digital levels from Leica Geosystems, one of which is the Leica DNA03. Mea-
Citytunnel Malmö The “Citytunnel Malmö” project, a 17 km rail link which runs on the surface and under Malmö, is made up of several components: 11 km two-track section from Malmö’s main station to the Öresund Bridge, 6 km of which run through parallel tunnels below the city 6 km single track section heading east toward Trelleborg and Ystad Conversion of Malmö’s main station from a terminus to a through station New stations serving the city districts of Triangeln and Hyllie Work commenced on the Citytunnel in 2005 and should be complete by 2011. The largest contract was awarded to the Malmö Citytunnel Group (MCG), a consortium formed by construction companies Aarsleff A/S and E. Pihl & Søn A/S from Denmark and Bilfinger Berger AG from Germany. All three firms are at the forefront of terotechnology.
surements are taken from a raised drill-steel reference station anchored in the limestone stratum. The deep and well-grounded anchor ensures that the levelling station is settlement-free.
Survey accuracy 0.15 mgon In addition to digital levels, Aarsleff A/S uses Leica Geosystems total stations for many surveying tasks surrounding the Citytunnel Malmö project. The total stations are models TCA2003, TCA1800, TCRP1201 and TCRA1101. A Leica TCRA1203 was used to control the tunnel-driving machine. "Under the terms of our contract we were obliged to use a total station with a measurement accuracy of 0.15 mgon. As only Leica Geosystems have instruments available with this high level of accuracy we had no difficulty in making the decision," recalls Kenn Hoby Andersen and adds: "That is not the only reason why we are using instruments from Leica Geosystems. Our general surveying policy is based on Leica Geosystems technology.“
The map shows the course of the “Citytunnel Malmö“ project: From 2011 trains will no longer have to go around the city to reach the Öresund bridge, but can go right through – or rather under – it. This also involves the construction of two new stations – Triangeln and Hyllie.
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In the Middle of the Rhine by Jürgen Reineke
The German energy provider “Energiedienst” is undertaking an ambitious project at Rheinfelden on the Rhine river. By 2011 four 6.5 metre diameter bulb turbines with an output of 25 megawatt each will be installed in the new turbine house on the Swiss side of the Rhine. One of the challenges is underwater excavation in the bed of the Rhine. The new facility will raise the generating capacity at the historic hydropower site in Rheinfelden from its present 26 MW to 100 MW. Since September 2006 contractor Schleith GmbH, Waldshut has excavated 1,200,000 m³ of rock and soil from the riverbed. A very challenging task – as a large part of the excavation is carried out directly in the Rhine and underwater. Three crawler excavators were fitted with 3D GPS machine control systems in order to meet the high requirements for performance, accuracy and above all robustness. For machine navigation Schleith opted for a robust GNSS solution, the Leica MNS1200 GG, in tandem with a 3D excavation control system provided by Leica Geosystems distribution partner Gritzke. The control system uses integrated satellite-aided positioning. The 3D application compares the actual
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survey data with the digital ground model created during the design process and displays the difference on the monitor in the form of a rapid 3D real-time animation. The seamlessly combination of components and the latest CANBUS 2.0B technology make the system a simple to operate, productive tool. Particular emphasis was placed on the robustness of the components. Sensors (V2A housing, accuracy 0.09°) tested under the harshest conditions, data cables layed in a hydraulic hose and protected with steel mesh and a PC and monitor selected to meet the highest requirements all ensured that the excavator control system could withstand the rough conditions prevailing at this construction site. The Leica MNS1200 GG is a surveying instrument at the forefront of innovative technology. Leica GPS1200 uses SmartTrack technology for excellent signal quality and SmartCheck for the highest reliability. Both systems in combination provided Schleith with one of the most productive and powerful packages currently available. Complex earthworks and underwater excavations are being carried out to centimetre-accuracy, without any other setting-out aids, precisely and independently on each area of the construction site.
Non-stop Paving by Volker Kuch
Often operating around the clock, Belgian civil engineering and building firm Betonac is using Leica PaveSmart LMGS-S on two slip-form concrete pavers. Runways and motorways are their main areas of application. Leica PaveSmart LMGS-S is a 3D machine control system developed specifically to control concrete slip-form construction. Two total stations and various inclination sensors control the line and level of the concrete paver. There is no longer a need for tension wire control systems on either side of the machine. Total station positioning allows the system to directly control the paver in the 3D ground model of the road or any other surface. The system can be used for every conceivable arrangement of equipment and across the whole spectrum of slip-forming applications. Betonac NV specialises in the field of civil, structural and highway engineering construction and is mainly engaged in public works. The Belgian company, with its headquarters in Sint-Truiden, has been using two Leica PaveSmart LMGS-S systems – one each on a Gomaco GP2800 and a Gomaco Commander III – since April 2003. Working with the system has long become routine for the slip-form crew. In the meantime they have amassed an impressive list of projects completed using this solution, mainly in Belgium, Lux-
embourg and France, such as the highways E40 (A10) Brussels – Ostend and E411 and E25 in Luxembourg, as well as the Airports Charles de Gaulle (Paris), Bierset (Liège) and South Charleroi (Brussels). There were a number of deciding factors for Betonac in the acquisition of the two systems: “We can operate non-stop for 24 hours and thus dispense with the need for end-of-day joints. Adjustments to line and level are possible at any time. The system displays the actual construction tolerances and therefore provides another excellent means of extended quality control,” says Chief Engineer Ludo Philtjens. It is not just the modern technology that justifies this investment for Betonac. Further directly quantifiable advantages can be seen every day in logistics, in improvements to working processes and in quality assurance. The consistent, reliable quality of production even during round-the-clock operation is particularly valued. After all, any mistakes cast in concrete are inevitably associated with high costs. This is where the Leica PaveSmart integrated surveying routines are vital. By working in real time and logging the achieved quality, they provide continuous and permanent assurance to everyone involved. The crew are able to check the operation of the paver at any time and optimise the accuracy and material consumption of the machine. “Concrete pavement has never been this comfortable,” enthuses Ludo Philtjens.
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Leica Builder in the “Green Industry” by Erwin Bauer
Garden and landscaping company Dukat is very pleased with its new Leica Builder Theodolite with electronic distance measurement combined with a PDA and seamless interface to Dataflor CAD and other specialist landscaping industry software. Enormous time-savings and the ability to create drawings even without specialist knowledge of surveying have convinced garden and landscaping expert Jürgen Dukat. When he attended a seminar last spring on site and quantity surveying, hosted by Leica Geosystems sales partner Dataflor, Jürgen Dukat was still sceptical about whether the acquisition of a CAD-supported surveying solution for his garden and landscape construction business in the form of the Leica Builder and PDA would really pay its way. “What finally convinced me was the ability of the system to link CAD
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drawing data recorded on site with my own specialist software for producing bills of quantities. I later confirmed in practice on several occasions that the system was capable of being operated without any specialist surveying knowledge,” explains Dukat. The Leica Builder, Dataflor software CAD V6 and GreenXpert complement one another perfectly – they are ideal for many applications in garden and landscape construction.
Impressed by understandable surveying system One of the first projects was a survey of a 120 m diameter retention basin for the re-flooding of some marshland. The survey took less than two hours to complete. As is common with many local authority construction works the client required Dukat to submit an electro-optic survey for design verification and documentation of quantities. The first stage was to survey about 90 points and then link these using the
software module “Digital Terrain Model” from Dataflor before producing the associated earthworks volumes automatically in the form of a schedule. “Earlier I would have given such a survey to a surveying office, which would have charged me several hundred Euro. Now we can produce fully understandable calculations in a very short time backed up by exact CAD drawings. The possibilities of Leica Builder have allowed us to achieve very high standards in design, job preparation, and quantity surveying whilst providing the customer with a thoroughly professional service,” says Dukat.
vate garden contracts is also worthwhile. The construction manager appreciates the accuracy that the integrated surveying solution offers: “Surveying a site with a tape is very time-consuming. On the other hand with Leica Builder the process is done quickly and reliably. The brilliance of the system lies in the fact that for each point surveyed I also receive its height. I now have accurate information available to me that earlier I would have had to roughly estimate or spend a lot of time calculating. All slopes, angles, even curved shapes correspond exactly with the real situation on site. The system is therefore very valuable to us in design, execution and billing.”
Shortly afterwards, the new equipment was used to survey some parkland with an area of around 40,000 square metres. Every individual tree and all the planted and grass areas were picked up and the annual maintenance and development plan for the park drawn up based on this accurate inventory. “Without Leica Builder we would have certainly needed a week for the survey alone. With the new system we were finished in a day and a half. The detailed CAD inventory drawing allowed us to calculate areas quickly. Based on this I estimated the cost of each task and was able to produce an exact quotation for the maintenance work,“ explains Dukat’s construction manager Peter Reintjes.
Not only does the total station supply precise ground survey information for the design and tender stage: thanks to the integrated interface with the CAD program it can transmit the drawing data from the surveyed site immediately over a wireless Bluetooth® connection to a hand-held computer (PDA) where it can be displayed as a CAD drawing. The user does not have to bother with survey sheets or coordinate lists. The newly surveyed points, lines, and areas can be viewed on-screen. Further details can be added to the drawing back in the office on a PC using Dataflor CAD software.
Highly accurate drawings
About the author: Dipl.-Betriebswirt Erwin Bauer is editor-in-chief of the professional journal bi-GaLaBau.
Peter Reintjes believes using a total station for pri-
Leica Geosystems and Dataflor Dataflor is the leading software provider for the "Green Industry" in Germany, Austria and Switzerland. It employs a staff of 60 at nine offices in Germany. Dataflor plans to increase customer satisfaction with this complete solution and has recently become a development and sales partner of Leica Geosystems for the garden and landscaping sector. Dataflor now offers several surveying solutions with Leica Geosystems sensors, for example Leica Builder, which can seamlessly exchange data in both directions with Dataflor office software.
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Rising High with GPS Network by Agnes Zeiner
The Burj Dubai is the highest-rise building under construction in the world. When completed in 2008 it will be the world’s tallest building, nearly twice the size of New York’s Empire State Building and higher than the current title holder, the Taipei Financial Center (Taipei 101) in Taiwan. The final height is being kept secret. Not a secret on the other hand, is the unique monitoring system Leica Geosystems developed together with the Chief Surveyor of Burj Dubai. In recent years there has been considerable interest in the construction of super high-rise buildings, primarily in the Far East. These buildings are subject to strong external tilt effects caused, among other things, by wind pressures, unilateral thermal effects through exposure to sunlight, and unilateral loads.
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Such effects are a particular challenge during the construction phase of a high-rise building, in as much as the high-rise building under construction is also subject to tilt effects and will at least temporarily lose its – usually exactly vertical – alignment. The Burj Dubai in Dubai, UAE, will rise to a height of over 800 m when completed in 2008. In addition to being very tall it is also quite slim and it is anticipated that there will be movement of the building at upper levels due to wind loads, crane loads, construction sequence and other factors. The self-climbing formwork system for the building is complex due to the shape of the structure and requires a large number of control points – currently over 240 are installed. Douglas Hayes, Chief Surveyor in Burj Dubai Tower, and Joel van Cranenbroeck, Business Development Director at Leica Geosystems, developed a complete-
ly new procedure to provide reliable coordinated points at the top of Burj Dubai using GPS observations combined with a network of precision inclination sensors. At the beginning of construction, six permanent benchmarks were established and precisely surveyed around the site. “From ground to about Level 20 resection was possible from the external control marks, which are located about 100 to 150 m from the base of the tower. Observation redundancy was possible and very high quality results were achieved”, says Douglas Hayes. But above Level 20 this system was not applicable anymore due to obstruction from the upper decks of the formwork system and poor visibility. “The movement of the structure creates several problems for precise surveys. Theoretically, at any particular instant in time you need to know exactly how much the design centre line of the building is offset from the actual vertical axis and at that same instant you need to know the precise coordinates of the instrument. However, a ‘mean’ position for both elements taken over a short time period can provide a suitable solution”, says Douglas Hayes. A complex combination of GPS antenna/receivers, Total Stations, Continuously Operating GPS Reference Stations Leica GRX1200 Pro plus Leica GPS Spider and Leica Geo Office Software, together with Leica Nivel220 dualaxis precise clinometers, accurately determines and analyzes displacement of the tower alignment from the vertical axis. A dynamic model of the building has been developed and from this it has been possible to derive values at any given level for the effect of construction sequence, building design and solar effects. This ‘smallest GPS network for the tallest building in the world’ can be used for tower monitoring both during construction and after completion of the structure”, summarizes Douglas Hayes: “If the Nivel200 Network is integrated with other monitoring information it will provide a complete system of structural monitoring.”
The “Vertical Cities” Concept “The challenge taken on by the vertical conquest of space is not to beat height records but to redefine dignified life in large communities. Authentic social commitment lies in developing an innovative model of vertical construction that unites revolutionary technological concepts capable of exceeding the 500 m height limit and the new bio-ecological models of town planning and architecture in a new philosophy of life,” say the Spanish architects Javier Pioz and Maria Rosa Cervera. Overpopulation, obsolete urban models with all their rising problems, and the non-acceptance of the common 500 m limit led them to develop their “Vertical Cities Concept”, based on the consideration that nature shows us how to build structures (Bionic Architecture). Their thesis: In massive nuclei and where land is scarce “Vertical Cities” allow the ecological expansion of cities. For Pioz and Cervera, buildings up to 1,228 m high (equivalent to 300 floors) with 100,000 inhabitants are the future – for mankind as well as for the environment: “Nature has all the answers; in time man will learn all the questions.”
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Russia goes for Leica ADS40 by Sergey Alexandrovich Loginov
The Russian National Research Institute for Cadastral Surveying, VISKHAGI, has a long tradition in the fields of aerial photography and cadastral surveying. Formed in 1932 as the Agricultural Aerial Photography Authority, it has been taking and working with aerial photographs for 75 years. Recently it has been using two Leica ADS40 airborne digital sensors. Sergey Alexandrovich Loginov, First Deputy General Director and Chief Engineer, writes about his experience for the “Reporter”. At the end of 2003, as a part of a World Bank tender, VISKHAGI acquired two Leica ADS40 airborne digital sensors. Leica Geosystems has been very support-
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ive and provided us with excellent service in both administrative and technical areas. With the help of the experts at Leica Geosystems we have installed a computer centre for processing digital data including 12 work stations, software and two high-performance servers, each with 12 terabytes of hard disk storage capacity.
Delayed first use Unfortunately we were not able to use the two new Leica ADS40 sensors straight away. On the one hand we were delayed by bureaucracy and on the other by important modifications we had to make to our existing technical equipment. We learned from the first test flights that, in addition to weather conditions playing an important role in flight planning, it was necessary to fly the plane in the “correct"
manner, i.e. special requirements for creating digital aerial photographs had to be taken into account.
Expectations fully and completely fulfilled From the results of the first working flights for data collection it was apparent that the Leica ADS40 sensors fulfilled all our expectations. With no increase in flight costs and elimination of photochemical processing of the aerial photographs, the result is a reduction in total cartography costs. We have found that the sensors deliver very high quality images, and because of the constant stereo angle they are eminently suitable for stereo applications and ideal for orthophotos. Through the use of one or more GPS base stations an accuracy can be achieved that is adequate for 1:2,000 maps without having to use fixed coordinate points. This allows considerable cost reductions to be made in the associated terrestrial geodetic surveying tasks.
VISKHAGI VISKHAGI is a state organization and part of the Federal Russian Land Survey Register Agency, which employs 3,500 staff in 13 locations throughout Russia. Between 1995-2000 the technical equipment used for aerial photography was completely replaced; for example VISKHAGI purchased nine Leica RC-30 cameras – and became the largest single user of RC-30 cameras in the world. The flights were made in AN-30 aircraft traditionally used for aerial surveying, stemming from the Soviet era. In addition to aerial photography VISKHAGI also carries out geodetic work in other areas such as the creation and expansion of geodetic coordinate grids, calibration of aerial photographs and other activities involved in highly accurate land surveying.
The Leica ADS40 sensors are used for 1:2,000 scale maps in the following manner: Flying height approximately 2,500 m Ground image resolution 20-25 cm Use of GPS base stations within a radius of 50 km Afterwards the recorded ground data are processed. Aerotriangulation is carried out and corrected without coordinated land stations to a local accuracy of 15-20 cm.
Intensive use We were able to work intensively with the Leica ADS40 sensors. For example during summer we photographed a large part of Moscow (over 3,500 km²) to a resolution accuracy of 15 cm. Our experience to date with the Leica ADS40 sensors clearly shows that not only do we have the latest technology available to us for cadastre surveying applications, we are also able to make considerable financial savings, which benefit Russian taxpayers.
One of the Leica ADS40 airborne sensors, mounted in the aircraft.
VISKHAGI traditionally uses AN-30 aircrafts, stemming from the Soviet era.
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Earth Dam Monitoring with GPS Survey by Agnes Zeiner
The Karkheh is the third largest river in Iran by water yield, after Karun and Dez. In the past its water richness was a constant danger for the west and southwest regions of the country. Seasonal floods and resulting extensive damage were characteristic of the Karkheh river forpeople living in the region. So when Karkheh dam was completed in 1995 it was a source of great relief and huge benefits to the people. Using GPS to monitor this huge structure, which is among the world’s 10 largest dams, was a task undertaken by MahabGhods Consulting Engineers Company, situated in Tehran. The last eight years MahabGhods provided an accurate yet cost-effective method for monitoring the Karkheh dam in Khuzestan Province.
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The construction of the Karkheh dam in 1995 (located near Andimeshk) eliminated the dangers resulting from the Karkheh river for the lands of downstream plains in Khuzestan Province. Storage and regulation of water, hydroelectric power generation amounting 934 GWh/year, and prevention of destructive floods were the main objectives of Karkheh dam. The earth dam has a total length of 3,030 meters and a height of 127 meters, with a reservoir capacity of 7.6 billion cubic meters. Experts of the Microgeodesy and GPS divisions of the Geomatic department of MahabGhods Consulting Engineers Company explain the challenge of the project: “Because of the large extent of the structure, conventional methods failed to satisfy monitoring requirements, as they required much time and provided less accuracy in this case. Besides, earth
dams' movements are more substantial than concrete dams. We recommended combining vertical preciselevelling networks with horizontal GPS monitoring networks to complete the survey of the dam.”
to collect data from a total of 119 points on- and off-dam and nearly 125 height difference observations in both backward and forward direction were collected using precision levels.
One dozen GPS monitoring surveys
Following analysis of the data MahabGhods reported movements of the dam over the eight-year period to be within the tolerance limits. “It is evident that the displacements do not exceed the accuracy requirements and network sensitivity” says the expert. She concludes by saying “using GPS helped to show the movements accurately and the horizontal results were complimented by the precise levelling network.”
Since 1999, MahabGhods has performed 12-epoch GPS monitoring surveys in off-dam and on-dam networks of Karkheh dam. “GPS has a supreme capability in horizontal positioning, but not in the vertical direction, because of special satellite constellation in which satellites are configured asymmetrically with respect to the vertical direction. Besides, GPS heights do not always fit with the actual shape of the earth. So it was essential to have a levelling network together with a GPS horizontal network”, says Ms. Nasim Rajabi Nazari, one of the experts at MahabGhods. Leica Geosystems’ GPS receivers were used
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Keeping Track of Moving Structures by Marc Reinhardt
How does a floodgate deform relative to the water level? What is the behaviour of the vibrations of a wind turbine tower? The Geodetic Institute at Leibniz University, Hanover sought answers to these challenging questions with the help of a Leica HDS4500 laser scanner. Professor Hansjörg Kutterer and his Research Assistant Christian Hesse from the Geodetic Institute at Leibniz University, Hanover have taken advantage of the possibilities of kinematic laser scanning. Using a stationary Leica HDS4500 scanner they studied the rapid movements of construction works such as canal locks and wind turbine structures. After extensive measurements they concluded that terrestrial laser scanners can be used to considerably expand the sensors used for engineering geodetic surveying in the field of geometric object detection and moni-
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toring. The continuous, concurrent readings in three dimensions capture rapid changes very accurately.
Lock gates surveyed in two modes One such project in the study was the canal lock complex “Uelzen I” between Hanover and Hamburg. The locks are one of two hydraulic structures of the Elbe-Side-Canal. The lock complex is 185 metres long and has a filled volume of 54,000 cubic metres. The floodgate itself is twelve metres wide and eleven metres high and stands seven metres above the water level when closed. The scientists from Hanover carried out 3D and 2D surveys of the locks, whereby each method has its own strengths and weaknesses. According to their overall findings Hansjörg Kutterer and Christian Hesse concluded that terrestrial laser scanning offers a unique way of determining the geometric deformation of the floodgate under changing loads. The task is made even easier because no signal is required from the object being surveyed. Of
Geodetic Institute at Leibniz University The Geodetic Institute at Leibniz University, Hanover looks back on a long history of geodetic teaching and research (the first academic chair was established in 1881). Today there are two specialist departments each headed by a professor. The Department of Engineering Geodesy and Geodetic Evaluation Methods (headed by Prof. H. Kutterer) developed out of the Department of General Surveying. The second department focuses on Area and Real Estate Management and was established with the arrival of Prof. Winrich Voss in 2006. Currently the Institute employs 16 people including nine doctoral candidates. On-going research work is concentrated on the improvement and extension of measurement and analysis methods used in rapid and high quality precise three-dimensional object surveying and analysis using engineering geodesy sensor systems, in particular terrestrial laser scanning. In addition to standard instruments such as total stations the Geodetic Institute Hanover uses terrestrial laser scanners (Leica HDS4500) and sensor systems from the field of metrology (Leica Lasertracker LTD640 and TPS5000).
key importance is the system’s ability to take readings rapidly with great accuracy and time resolution.
Wind turbine vibrations In the study of the wind turbine (manufactured by Tacke) at the Schliekum windfarm, the team from the Geodetic Institute decided to use the 2D-mode of the Leica HDS4500. Because the sampling frequency was too low and due to the lateral expansion of the object, a survey of the surface in 3D-mode was not suitable. 5,692 profiles were used to analyse the data. They were recorded at a rate of 12 profiles per second and produced a detailed record of the vibration characteristics of the tower. This data will form an important foundation for more in-depth monitoring of structures.
One of the research areas the Geodetic Institute at Leibniz University in Hanover focuses on is the field of three-dimensional object surveying.
The Global Magazine of Leica Geosystems | 19
Beyond Scanning by David Danko
At the end of 2006, CADWorx fieldPipe for Leica fieldPro was presented by Leica Geosystems and the software company COADE. It was launched together with the newest version of the mobile CAD software Leica fieldPro and is specially designed to build 3D plant models of existing piping systems. As-built models are created in real-time, on-site, and without any post-processing. Customer David Danko, laser scanning project manager with Falk Engineering & Surveying in Indiana, was among the first to try out the system. He told the “Reporter” about his experiences with the new package. To gather information for the production of as-built models and drawings of plant and piping systems, Falk Engineering and Surveying uses the precision capabilities of laser scanning equipment. The instrument produces ‘point clouds’ – millions of 3D data points that match the outlines of all the items in the area being scanned. But producing 3D models of piping from point cloud data is a challenge.
The 3D Model is done while surveying.
Even though the production of the 3D model would best be done in the field by the person doing the surveying, this is something that has not been possible in the past. What you are left with is a faithful
20 | Reporter
representation of the site and piping systems with its components, such as pipes, elbows and valves, represented by cylinders, tori and blocks. While representative and accurate, these are without any intelligence. This is why, when we heard of a system that would allow the person surveying the system to leave the site with a complete intelligent model, we had to investigate.
Leave site with complete 3D models What we were introduced to was CADWorx fieldPipe for Leica fieldPro. With other software we have used, you had to go back to the office and process the point cloud information to get a 3D model. With the new software this is totally different. As you survey, you actually see the piping system being built, so when you leave you have a complete and accurate 3D model of what you’ve surveyed. Not only that: the model is intelligent, with everything in it and all the components identifiable as pipes, elbows, valves etc. Just click on an item and you get all the information about it. Working with Total Stations and CADWorx fieldPipe proved to be so much quicker. We saved six to eight hours just for one spool piece. That’s less than 50% of the time it would normally take us. When we left the site, the model was complete. With this new package, pipe runs develop as you’re surveying the installation. I’ve never seen anything else do that. It was easy to set up and use. Once I started doing it, it was pretty natural, intuitive and easy to use. It just made sense to me right from the start. Most of our clients are repeat customers, and to keep them coming back, we stay up-to-date and look for solutions from which they can benefit. One of the best things for us in CADWorx fieldPipe for Leica fieldPro was that clients were impressed with the drawings that we produced and gave back to them as a deliverable. That’s great for our clients, and that’s what matters most.
Keep Up With the Youngsters Todd Gokey is project engineer for Barrett Paving Materials Inc., the oldest contractor in the nation, established in 1864. Today the Syracuse, NY, division he works for does airport and highway reconstruction work, and for the past three months Gokey has been working with Leica Geosystems GPS indicate systems on two dozers and an automatic system on a Cat G12 motor grader. Typically, operators are expected to meet tolerances of plus or minus 6 millimeters – one-quarter of an inch. “One of our motivations for GPS,” says Gokey, “was that New York State DOT (Department of Transportation) has set up a Leica GPS Spider RTK network with their own base stations. Their intent is that their inspectors will use rovers, and they have announced they’re going to change the spec books to accommodate automated machinery. The specifications on
a recent job included that the contractor had to buy the state a base station and a couple of rovers. “The way we’re set up now, we use the rover for all our survey work, including drainage structures, pipes, and the center line for the pavers. The excavator does the bulk of the work, and the dozer comes behind and gets the fine grade done. Leica Geosystems just came out with a 3D system for excavators (Leica DigSmart 3D), and I’m looking into that. If we had GPS on the excavator, the operator would know exactly what he’s digging and where. And with a system on an excavator, the dozer and excavator would almost be a standalone crew.” Reprinted with permission of Grading & Excavation Contractor magazine. www.gradingandexcavating.com
The Global Magazine of Leica Geosystems | 21
Sharp Lines on Site by Petra Ammann
With its outstanding optics and proven Power Range Technology™ the new self-levelling precision line-laser Leica LINO™ L2 is a little sensation. Its strengths: precise and perfectly visible laser lines. The new Leica LINO™ L2 was jointly developed with users so that it would integrate optimally into normal working practices. All that tedious messing about with water levels, plumb lines or measuring rules is at last consigned to the past: with the new Leica LINO™ L2 these everyday alignment and positioning tasks are completed quickly and precisely. The clear red laser beam simply displays the required lines – horizontally or vertically, and even intersecting lines.
Excellent visibility and precision The quality of the optics in the device is important for the lines to be highly visible and sharp. The Leica LINO™ L2 is equipped with proven Leica Power Range Technology™ to guarantee excellent visibility – the lines are easy to see even in a bright environment. Thanks to the extremely large aperture angle of the optics, the device projects amazingly long lines on to the wall, making it ideal for transferring reference points onto nearby walls or ceilings. With an accuracy of +/- 1mm over 5 m the Leica LINO™ L2 is the most precise device in its class and will help avoid expensive mistakes caused by inaccurate measurement transfer.
22 | Reporter
Simple, quick and self-levelling Even someone who has never worked with a level before can project exact horizontal and vertical lines on to a wall in next to no time. With the new Leica LINO™ L2 these everyday alignment and positioning tasks are completed extremely quickly and precisely. No painstaking levelling of the device is required – it is self-levelling! And if the inclination of the supporting surface is too large then the Leica LINO™ L2 detects this itself and does not project the line, eliminating potential errors. The self-levelling feature can be switched off by locking the device. This not only protects the Leica LINO™ L2 during transport, it is also useful when projecting from unusual positions. Using the Leica LINO™ L2 to project over long distances outside is child’s play thanks to the pulse function with energy saving mode and detector (accessory).
Clever accessories With the device are included a magnetic multifunctional adapter, which allows setting up in a wide range of situations, and a target plate – a very useful tool when a projection surface is required in a unenclosed space. The ball and socket adapter allows projections from surfaces sloping at all angles and the original Leica LINO™ bag provides a practical and safe way to transport the device to and from site.
News
First Leica ADS40-II in Africa
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Leica Rugby 50 and Leica Rugby 55: Designed for interior and general construction applications With the Leica Rugby 50 and Leica Rugby 55, Leica Geosystems adds two further members to the Rugby Laser family. Similar looking, the two new lasers are designed for different applications: The Rugby 50 is dedicated to general construction contractors, being a tough, affordable laser with a revolutionary simple feature: only one single button. Whereas the Leica Rugby 55 is designed for the interior contractor – a versatile laser, perfect for almost any leveling and alignment job.
Leica Rugby 50: tough and reliable.
Leica Geosystems’ distribution partner GIMS (Pty) Ltd is proud to announce the first Leica ADS40-II Airborne Digital Sensor is now operational in Africa. In November 2006 Siyazi DTM Services, situated in Longmeadow, acquired this state of the art Digital Sensor with its pushbroom technology. This acquisition has catapulted them into the digital imaging industry and will enable the company to meet the urgent demand for geospatial data that is required in the fast growing South African economy as well as in Sub-Saharan Africa. Chris Schutte from Siyazi DTM services says, “We are currently working on projects for Mbombela District Municipality, Tshwane Metro, Rustenburg Platinum Mines, Potgietersrus Platinum Limited and Sishen Iron Ore Mines in Thabazimbi. We are planning to have workshops all over South Africa to introduce the new system and its advantages to prospective clients.”
Leica ADS40-II with two new sensor heads.
Leica SmartPole: Setup On-the-Fly With Leica SmartPole, the coordinates and orientation are determined On-the-Fly whilst conducting the survey, using both GPS and TPS. This saves time in planning and executing the survey. With SmartPole, the most convenient location for positioning the total station can be chosen. Traversing is no longer required, each TPS set up can be conducted independently with new coordinates and orientation being determined with SmartPole GPS. Once the TPS orientation and coordinates are known, all measured points are automatically updated. The user can chose control points that deliver the best geometric distribution whilst simultaneously completing the survey. This ensures maximum flexibility and hence productivity.
Imprint Reporter: Customer magazine of Leica Geosystems Published by: Leica Geosystems AG, CH-9435 Heerbrugg Editorial Office: Leica Geosystems AG, CH-9435 Heerbrugg, Switzerland, Phone +41 71 727 34 08, reporter@leica-geosystems.com Contents responsible: Alessandra Doëll (Director Marketing Communications) Editor: Agnes Zeiner Publication details: The Reporter is published in English, German, French and Spanish, twice a year. Reprints and translations, including excerpts, are subject to the Editor’s prior permission in writing. © Leica Geosystems AG, Heerbrugg (Switzerland), April 2007 Printed in Switzerland
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